The question was decided in an ingenious manner by Captain Atkinson. Some distance above the fork in the stream lay a big log near the water’s edge. Doubtless it had been carried down in some freshet. At any rate, to the Ranger’s shrewd mind it suggested a way of solving the problem. Under his direction the boys rolled it into the stream, wading out with it as far as they dared. Then they watched it as the river swept it along. At the fork a current caught the log and whirled it off down the branch stream. “That decides it,” declared Captain Atkinson, “we will follow the fork of the Rio. If Jack was on anything that floated it would have been swept from the main stream in the same way as that log.” They then proceeded to find a way to cross the main stream so as to get on the bank of the branch current. They soon found a ford about a mile up the river. After some cautious reconnoitering Captain Atkinson decided to cross the stream at that point. But he warned the boys that they might have to swim with their horses before they reached the other side. “It is impossible to tell if there aren’t deep holes in the middle of the stream,” he said. “In case we do flounder into any of them just fling yourself from the saddle, keeping hold of the pommel. Then let the ponies do the rest and they will land you safe and sound.” For the first few yards all went well. The water came up to the ponies’ withers, but it did not appear to get deeper. Ralph was just congratulating himself that they would get across with ease and safety if things continued that way when his pony suddenly floundered into a deep hole. Instantly it lost its footing and went clear under. Ralph had not time to extricate his feet from the stirrups, and was carried with it. As he vanished from view under the turbid current an alarmed cry broke from both Captain Atkinson and Walt Phelps. CHAPTER XV. A “BLANK WALL.” “He’s drowning!” cried Walt in alarmed tones. “It is just as I feared,” cried Captain Atkinson, “the pony struck a water hole and————” “Look, there’s the pony now!” cried Walt as the little animal reappeared and began swimming for the bank. “But where is Ralph?” Without waiting to make any reply to Captain Atkinson, Walt suddenly wheeled his pony. Down the stream he had seen an arm extended above the muddy current. He knew that it was Ralph’s. There was no hesitation in the boy’s manner as he turned his pony, and, plunging the spurs in deep, drove him through the water. All at once Walt and his pony floundered into the same hole that had been Ralph’s undoing. At the same instant a sudden swirl of the current caught Ralph, who, though half drowned, was making a brave struggle. The momentary halt was the chance that Captain Atkinson had been looking for. He had followed close on Walt’s heels and now, while the latter was struggling to maintain a hold on his swimming pony, the captain of the Rangers uncoiled his lariat.